Abstract

Abstract: The paternity patterns observed in decapods reflect the mating strategies and tactics employed by different species. However, these patterns may be altered by fishery management, particularly through male-biased harvesting, which affects the natural sex ratio and subsequently influences mating success and reproductive success. This study examined the reproductive strategies of the kelp crab Taliepus dentatus, revealing that, unlike other Majoidea crabs, T. dentatus demonstrates a single paternity pattern, apparently unaffected by fishing pressures. Histological analyses revealed a seminal receptacle non-compartmentalised, full of seminal material. Despite this, contrasting mating schemas in laboratory experiments (simultaneous vs sequential mating) discriminated the impacts of males and females in mating success, revealing that females were receptive approximately 50% of the time, but did not exhibit mate selection during the pre-copulatory period. Additionally, results showed that mating was mostly influenced by the presence of risk of sperm competition, as males rarely mated or displayed post copulatory guarding behaviour when other males were present. Finally, despite traits promoting multiple paternity exhibits for T. dentatus, factors such as limited natural encounters, short copulatory durations and full seminal receptacles likely contributed to the observed genetic monogamy. This research emphasises the need 1) to understand reproductive behaviours using multiple approaches (i.e. genetics, behaviour and histology) and 2) to perform contrasting mating experiments in sequential and simultaneous designs. Significance statement: Patterns of paternity are a good input in efforts to develop biologically based fisheries management. This is especially sensitive for crustaceans because one of the most commonly used fishery controls in this group is sex-biased capture and reproductive success in these species can be sensitive to change in sex ratios if multiple paternities are present. In this study, we approached the paternity study in a harvested crab using a multiple approaches including, laboratory mating experiments, genetics and histology of the sperm receptive structure of females. In addition, we used laboratory experiment with diverse socio-sexual scenarios in simultaneous and sequential mating schemes. This allows us to evaluate mate selection in both sexes in a novel way. The latter may be of great interest to a wide range of researchers, not only who work in crustaceans. © The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature 2025.